From the admins on Glen Campbell Forums On The Net:
A photo of Glen Campbell previously available only to fans of Glen's "Official International Fan Club"
managed by club leaders (then-known as "club secretaries") Rosemary, Paula and Thurley
during the 60s & 70s and based in Los Angeles, CA.

GLEN CAMPBELL COLOR PHOTO FROM HIS FAN CLUB IN HOLLYWOOD.jpg (1.1 MiB) Viewed 596 times

(Photo courtesy of Glen Campbell Enterprises and The Archives of Glen Campbell Forums On The Net)

I did a quick search on this calendar (and will re-check)...it appears that The Esquires only opened one other time in 1965 for The Beach Boys: September 4th. By this date, Glen was no longer touring with The Boys. This info helps to confirm the Feb. 21 date and concert--as well as the photograph's date!